Scripting.Dictionary likes to add values for no reason, when you look a value up! Demonstrated with a 30 second example:
Create a new worksheet, and fill in A1:A4 = {1,2,3,4}
Insert a new vba module and add this code
Public Sub test()
Dim rowIndex As Integer
'
Dim dict As Scripting.Dictionary
Set dict = New Scripting.Dictionary
For rowIndex = 1 To 4
dict.Add Trim(Sheet1.Cells(rowIndex, 1).Value), rowIndex
Dim notEvenAddingSoWhyAreYouAdding As Variant
notEvenAddingSoWhyAreYouAdding = dict(Sheet1.Cells(rowIndex, 1).Value)
Next rowIndex
End Sub
Put a breakpoint on Next rowIndex
Run the sub and inspect the value of dict. It now has two values, "1" and 1, as you can see in the image below:
What. The. Hell?!
I realise I have the Trim(...) function in the dict.Add() line, which means there are two distinct keys in use, but why is it adding an extra value when it does a lookup?! That makes no sense whatsoever - now dict.Count would not give the value I would expect.
As you pointed out, you have two different keys, 1 and "1". If you try to access a key that doesn't already exist in the dictionary, it will add it automatically. It is strange behaviour.
I'd use something like this:
If dict.Exists(something) Then
myVariable = dict.Item(something)
End If
You creating one key as a string representing 1 (e.g. "1") and the key's item as the number 1 using the conventional dict.Add <key>,<item>.
Immediately afterwards, you shortcut add another with the number 1 as the key.personally, I shortcut the add/overwrite with dict.item(1) = "abc" but your method works as well.
tbh, I'm not even sure if .CompareMode = vbTextCompare would resolve a strin 1 to equal a numeric 1. In any event, you are currently on a vbBinaryCompare so there is no way it will match.
Related
I need to check if an object exists at a specified index in a List in Visual Basic.
What I have is
Dim theList As New List(Of Integer)({1,2,3})
If theList.Item(3) = Nothing Then
'some code to execute if there is nothing at position 3 in the list
But when I run the program I get System.ArgumentOutOfRangeException, saying the index is out of range. Of course it is, the entire point was to see if it does or doesn't exist. If "= Nothing" is not the way to check if something exists at that index, what is?
I am in my Application Development class and we are working on Windows Forms Applications using Visual Studio 2017, if any of that matters.
If you are checking a list of objects, you need to change two things.
The way to check for nothing is to use Is Nothing.
You can't even attempt to check items beyond the end of the list, so you must first check that the index you want to use is less than the number of items in the list'
You should change your code to
If theList.Items.Count > 3 AndAlso theList.Item(3) Is Nothing Then
'some code to execute if there is nothing at position 3 in the list
End If
Note the use of AndAlso rather than And in the If statement. This is required because it ensures that the check on item 3 happens only if there are at least 4 items in the list.
Also note that, in the code you posted, the list is a List(Of Integer). An Integer can never be Nothing, so the second part of you check is either not needed or you should be checking for = 0 instead of Is Nothing.
Any time you have a list you can only access members of the list, accessing an imaginary item outside of the bounds will result in the error you specified.. The integer datatype comparison to Nothing is a comparison to 0. IMO this use of nothing is not ideal. If you want nothing you might look at Nullable. Here is some code to take a look at.
Dim theList As New List(Of Integer)({0, 1, 2, 3})
For idx As Integer = 0 To theList.Count - 1 'look at each item
If theList.Item(idx) = Nothing Then
Stop ' item is 0
End If
Next
Dim i As Integer = Nothing ' i = 0
'Dim theListN As New List(Of Integer?)({1, 2, 3, Nothing, 5})
Dim theListN As New List(Of Nullable(Of Integer))({1, 2, 3, Nothing, 5, Nothing})
For idx As Integer = 0 To theListN.Count - 1 'look at each item
If theListN.Item(idx) Is Nothing Then
'item is nothing, not 0
Dim nullI As Nullable(Of Integer) = theListN.Item(idx)
If Not nullI.HasValue Then Stop
End If
Next
So rather simply I defined a test function:
Option Base 1
Function TestFunction(InputRange As Range)
Dim TestArray() As Variant
TestArray = InputRange
Debug.Print TestArray(5)
End Function
I then call it on a sheet with =TestFunction(A:A), and expect to see the value in row 5 printed to the Immediate window. Instead I don't get any output. The first 100 or so rows of A have data so I'd expect TestArray(5) to output something.
I've also tried changing the above to:
TestArray = InputRange.Value
and:
TestArray = Range(InputRange)
None of this seems to work.
The issue is when assigning a range to an array it is made into a two dimensional array regardless if it is one column or one row. So all references must refer to it as a two dimensional array:
Debug.Print TestArray(5,1)
I have to check a piece of user input against a list of items; if the input is in the list of items, then direct the flow one way. If not, direct the flow to another.
This list is NOT visible on the worksheet itself; it has to be obfuscated under code.
I have thought of two strategies to do this:
Declare as an enum and check if input is part of this enum, although I'm not sure on the syntax for this - do I need to initialise the enum every time I want to use it?
Declare as an array and check if input is part of this array.
I was wondering for VBA which is better in terms of efficiency and readability?
You can run a simple array test as below where you add the words to a single list:
Sub Main1()
arrList = Array("cat", "dog", "dogfish", "mouse")
Debug.Print "dog", Test("dog") 'True
Debug.Print "horse", Test("horse") 'False
End Sub
Function Test(strIn As String) As Boolean
Test = Not (IsError(Application.Match(strIn, arrList, 0)))
End Function
Or if you wanted to do a more detailed search and return a list of sub-string matches for further work then use Filter. This code would return the following via vFilter if looking up dog
dog, dogfish
In this particular case the code then checks for an exact match for dog.
Sub Main2()
arrList = Array("cat", "dog", "dogfish", "mouse")
Debug.Print "dog", Test1("dog")
Debug.Print "horse", Test1("horse")
End Sub
Function Test1(strIn As String) As Boolean
Dim vFilter
Dim lngCnt As Long
vFilter = Filter(arrList, strIn, True)
For lngCnt = 0 To UBound(vFilter)
If vFilter(lngCnt) = strIn Then
Test1 = True
Exit For
End If
Next
End Function
Unlike in .NET languages VBA does not expose Enum as text. It strictly is a number and there is no .ToString() method that would expose the name of the Enum. It's possible to create your own ToString() method and return a String representation of an enum. It's also possible to enumerate an Enum type. Although all is achievable I wouldn't recommend doing it this way as things are overcomplicated for such a single task.
How about you create a Dictionary collection of the items and simply use Exist method and some sort of error handling (or simple if/else statements) to check whether whatever user inputs in the input box exists in your list.
For instance:
Sub Main()
Dim myList As Object
Set myList = CreateObject("Scripting.Dictionary")
myList.Add "item1", 1
myList.Add "item2", 2
myList.Add "item3", 3
Dim userInput As String
userInput = InputBox("Type something:")
If myList.Exists(userInput) Then
MsgBox userInput & " exists in the list"
Else
MsgBox userInput & " does not exist in the list"
End If
End Sub
Note: If you add references to Microsoft Scripting Runtime library you then will be able to use the intelli-sense with the myList object as it would have been early bound replacing
Dim myList As Object
Set myList = CreateObject("Scripting.Dictionary")
with
Dim myList as Dictionary
Set myList = new Dictionary
It's up to you which way you want to go about this and what is more convenient. Note that you don't need to add references if you go with the Late Binding while references are required if you want Early Binding with the intelli-sense.
Just for the sake of readers to be able to visualize the version using Enum let me demonstrate how this mechanism could possibly work
Enum EList
item1
item2
item3
[_Min] = item1
[_Max] = item3
End Enum
Function ToString(eItem As EList) As String
Select Case eItem
Case EList.item1
ToString = "item1"
Case EList.item2
ToString = "item2"
Case EList.item3
ToString = "item3"
End Select
End Function
Function Exists(userInput As String) As Boolean
Dim i As EList
For i = EList.[_Min] To EList.[_Max]
If userInput = ToString(i) Then
Exists = True
Exit Function
End If
Next
Exists = False
End Function
Sub Main()
Dim userInput As String
userInput = InputBox("type something:")
MsgBox Exists(userInput)
End Sub
First you declare your List as Enum. I have added only 3 items for the example to be as simple as possible. [_Min] and [_Max] indicate the minimum value and maximum value of enum (it's possible to tweak this but again, let's keep it simple for now). You declare them both to be able to iterate over your EList.
ToString() method returns a String representation of Enum. Any VBA developer realizes at some point that it's too bad VBA is missing this as a built in feature. Anyway, you've got your own implementation now.
Exists takes whatever userInput stores and while iterating over the Enum EList matches against a String representation of your Enum. It's an overkill because you need to call many methods and loop over the enum to be able to achieve what a simple Dictionary's Exists method does in one go. This is mainly why I wouldn't recommend using Enums for your specific problem.
Then in the end you have the Main sub which simply gathers the input from the user and calls the Exists method. It shows a Message Box with either true or false which indicates if the String exists as an Enum type.
Just use the Select Case with a list:
Select Case entry
Case item1,item2, ite3,item4 ' add up to limit for Case, add more Case if limit exceeded
do stuff for being in the list
Case Else
do stuff for not being in list
End Select
Okay, this is doing my head in. I'm calling SetColumnError() on a DataRow object that has 20 columns, but no matter which ColumnIndex I use it sets the error text on column 0. The MSDN documentation makes it plainly clear that the error text is supposed to be set on the column that the ColumnIndex provides.
I'm trying to set error text on columns 1 and 2 (I normally use constants when doing this, I have just used the integers in this example code for simplicity). Why does the error text appear on column 0 and what should I be doing to get the text to show on columns 1 and 2? I'm not receiving IndexOutOfRangeException.
Here is the code I'm having trouble with.
Public Sub ValidateRows()
For Each dgvRow As DataGridViewRow In Me.DataGridView1.Rows
If dgvRow.DataBoundItem IsNot Nothing Then
Dim rowView As DataRowView = dgvRow.DataBoundItem
Dim rowData As MyDataSet.DocumentRow = rowView.Row
rowData.ClearErrors()
If rowData.Revision = rowData.Revision_old Then
rowData.SetColumnError(1, "You must change the revision")
End If
If rowData.InternalRevision = rowData.InternalRevision_old Then
rowData.SetColumnError(2, "You must change the internal revision")
End If
End If
Next
End Sub
I'm not sure, but I think the number of the column must be of the type "DataColumn".
I'm having some trouble with syntax options while writing a VBA Macro for Excel. In VBA you can call a method on an object in two different ways:
foo.bar(arg1, arg2)
or
foo.bar arg1, arg2
I absolutely detest the second sort of syntax because I find it lacks any sort of clarity, so I normally adhere to the first option. However, I've come across a situation where using the first option creates an error, while the second executes fine. (This may perhaps be an indicator of other problems in my code.) Here is the culprit code:
Function GetFundList() As Collection
Dim newFund As FundValues
Range("A5").Select
Set GetFundList = New Collection
While Len(Selection.Value)
Set newFund = New FundValues
' I set the fields of newFund and move Selection
The problem is in this next line:
GetFundList.Add newFund
Wend
End Function
FundValues is a class I created that is essentially just a struct; it has three properties which get set during the loop.
Basically, when I call GetFundList.Add(newFund) I get the following error:
Run-time error '438':
Object doesn't support this property or method
But calling GetFundList.Add newFund is perfectly fine.
Does anyone understand the intricacies of VBA well enough to explain why this is happening?
EDIT: Thanks much for the explanations!
Adding items to a collection is not defined as a function returning a value, but as a sub routine:
Public Sub Add( _
ByVal Item As Object, _
Optional ByVal Key As String, _
Optional ByVal { Before | After } As Object = Nothing _
)
When calling another sub routine by name and sending arguments (without adding the "Call" statement), you are not required to add parentheses.
You need to add parentheses when you call a function that returns a value to a variable.
Example:
Sub Test_1()
Dim iCnt As Integer
Dim iCnt_B As Integer
Dim iResult As Integer
iCnt = 2
iCnt_B = 3
fTest_1 iCnt, iResult, iCnt_B
End Sub
Public Function fTest_1(iCnt, iResult, iCnt_B)
iResult = iCnt * 2 + iCnt_B * 2
End Function
Sub Test_2()
Dim iCnt As Integer
Dim iCnt_B As Integer
Dim iResult As Integer
iCnt = 2
iCnt_B = 3
iResult = fTest_2(iCnt, iCnt_B)
End Sub
Public Function fTest_2(iCnt, iCnt_B)
fTest_2 = iCnt * 2 + iCnt_B * 2
End Function
Let me know if not clear.
This Daily Dose of Excel conversation will be helpful.
When you use the parentheses you are forcing VBA to evaluate what's inside them and adding the result to the collection. Since NewFund has no default property - I assume - the evaluation yields nothing, so can't be added. Without the parentheses it evaluates to the instance of the class, which is what you want.
Another example. This:
Dim coll As Collection
Set coll = New Collection
coll.Add Range("A1")
Debug.Print coll(1); TypeName(coll(1))
and this ...
coll.Add (Range("A1"))
Debug.Print coll(1); TypeName(coll(1))
... both yield whatever is in A1 in the debug.window, because Value is Range's default property. However, the first will yield a type of "Range", whereas the type in the 2nd example is the data type in A1. In other words, the first adds a range to the collection, the 2nd the contents of the range.
On the other hand, this works:
Dim coll As Collection
Set coll = New Collection
coll.Add ActiveSheet
Debug.Print coll(1).Name
... and this doesn't:
coll.Add (ActiveSheet)
Debug.Print coll(1).Name
because ActiveSheet has no default property. You'll get an runtime error 438, just like in your question.
Here's another way of looking at the same thing.
Let assume that cell A1 contains the string Hi!
Function SomeFunc(item1, item2)
SomeFunc = 4
End Function
Sub Mac()
' here in both of the following two lines of code,
' item1 will be Variant/Object/Range, while item2 will be Variant/String:
SomeFunc Range("A1"), (Range("A1"))
Let i = SomeFunc(Range("A1"), (Range("A1")))
'this following is a compile syntax error
SomeFunc(Range("A1"), (Range("A1")))
' while here in both the following two lines of code,
' item1 will be Variant/String while item2 will be Variant/Object/Range:
SomeFunc ((Range("A1")), Range("A1")
Let j = SomeFunc((Range("A1")), Range("A1"))
'this following is a compile syntax error
SomeFunc((Range("A1")), Range("A1"))
Set r = Range("A1") ' sets r to Variant/Object/Range
Set r = (Range("A1")) ' runtime error 13, type mismatch; cannot SET r (as reference) to string "Hi!" -- Strings are not objects in VBA
Set r = Range("A1").Value ' runtime error (same)
Let r = Range("A1") ' set r to "Hi!" e.g. contents of A1 aka Range("A1").Value; conversion to value during let = assignment
Let r = (Range("A1")) ' set r to "Hi!" e.g. contents of A1 aka Range("A1").Value; conversion to value by extra ()'s
Let r = Range("A1").Value ' set r to "Hi!" by explicit use of .Value
End Sub
I only add this to help illustrate that there are two things going on here, which could be conflated.
The first is that the () in an expression that converts the item to its Value property as stated above in other answers.
The second is that functions invoked with intent to capture or use the return value require extra () surrounding the whole argument list, whereas functions (or sub's) invoked without intent to capture or use the return value (e.g. as statements) must be called without those same () surrounding the argument list. These surrounding () do not convert the argument list using .Value. When the argument list has only one parameter, this distinction can be particularly confusing.